long shot here since it's been 3 years, but I'm curious do you throw it in neutral when you coast?
coming from a 94 manual runner I coasted a lot of big hills here in neutral which was a ok with a manual trans. But with my new truck 5th gen with auto trans I'm just not sure if coasting down in neutral is gonna cause any issues with the trans? I can't see why it would but I'm not familiar with these fancy auto shifting transmissions haha.
It does no harm to coast in neutral; if it did, Toyota (and all other manufacturers) would put a way to prevent it unless the driver did some special steps to do it.
If going down a long, steep hill, however, you should leave the transmission in gear, for that will provide engine braking, thus saving the friction brakes from over heating, and slowing the pads from wearing out.
The fuel savings from coasting in neutral are minimal, for even in gear, the transmission will be in top gear and the engine turning slowing, burning little fuel. (There are a few, very few, cars that actually turn off all fuel delivery to the engine when coasting, thus no fuel is used at all).
You cite coasting with a manual transmission, which is usually done by disengaging the clutch, not actually shifting. That was actually discouraged by some manufacturers (notably VW) for it put added stress on the throw out bearing. But for most cars now, the throw out bearing is better and causes little additional problems if you coast.
I know the 4Runner is not a hybrid (the 6th generation 4Runner is a mild hybrid), but for hybrids, it is imperative to leave the transmission in gear, for that is when regeneration occurs, which leads to the best gas mileage. (Regeneration is when the car's momentum is changed to electrical energy and stored in a battery for future propulsion, thus saving gas). Regeneration cannot occur if the transmission is in neutral.
For me, I just leave the transmission in gear, so I don't need to do anything when engine power is needed later.